Multilayer ceramic dielectric for inductor and inductor using same

Abstract

The present invention provides a multilayer ceramic dielectric for an inductor and an inductor using same, wherein a first anodic oxide film having a low porosity due to having relatively small pores or a relatively small number of pores is positioned on upper and lower surface layers, and a second anodic oxide film having a large porosity due to having relatively large pores or a relatively large number of pores is positioned on inner layers positioned between the upper and lower surface layers to make the dielectric constant high on the upper and lower surfaces and low in an inner region so that a current path operates efficiently on the surface sides, and the efficiency of magnetic field passage inside can be enhanced to improve high-frequency characteristics.

Description

Multilayer ceramic dielectric for inductors and inductor using the same

[0001] The present invention relates to a multilayer ceramic dielectric for an inductor and an inductor using the same.

[0002] An inductor is a passive component that utilizes the electromagnetic action generated by passing current through a wire wound around a core. Various types of inductors are being developed for high-frequency circuits, general circuits, decoupling circuits, and power circuits. While there are variable inductors with varying inductance, most are fixed inductors. In terms of shape, they are available in lead and surface-mount types, and structurally, they are classified into wire-wound, laminated, and thin-film types.

[0003] Inductors can be combined with capacitors to form resonant circuits, or used in filter circuits to filter specific signals or for impedance matching. Recently, alongside the advancement of electronic and communication devices, issues such as environmental and communication interference have emerged. Consequently, technology is advancing in terms of functional complexity, high integration, and high efficiency.

[0004] Accordingly, the applicant has filed an application for an inductor having a body composed of an anodic oxide film to satisfy the market's requirements for miniaturization and low resistance, and to increase the inductance value.

[0005] However, in the structure of the previously filed inductor, there is a need to make the current path operate more efficiently and to improve high-frequency characteristics.

[0006] [Prior Art Literature]

[0007] [Patent Literature]

[0008] (Patent Document 1) Korean Published Patent No. 10-2022-0091265

[0009] The present invention aims to provide a multilayer ceramic dielectric for an inductor capable of operating a current path efficiently and improving high-frequency characteristics, and an inductor using the same.

[0010] A multilayer ceramic dielectric for an inductor according to one feature of the present invention comprises: a surface layer composed of a first anodic oxide film having a relatively small porosity; and an inner layer provided below the surface layer and composed of a second anodic oxide film having a relatively large porosity.

[0011] Additionally, the surface layer comprises: an upper surface layer constituting the upper surface of the multilayer ceramic dielectric for the inductor; and a lower surface layer constituting the lower surface of the multilayer ceramic dielectric for the inductor.

[0012] In addition, the first anodic oxide film and the second anodic oxide film are composed of a porous layer having pores formed therein, and the diameter of the pores in the porous layer of the first anodic oxide film is smaller than the diameter of the pores in the porous layer of the second anodic oxide film.

[0013] In addition, the first anodic oxide film and the second anodic oxide film are composed of a porous layer having pores formed therein, and the density of the pores in the porous layer of the first anodic oxide film is lower than the density of the pores in the porous layer of the second anodic oxide film.

[0014] In addition, the first anodic oxide film comprises a barrier layer having no pores formed therein and a porous layer having pores formed therein, provided on one side of the barrier layer, and the barrier layer is located on the surface side.

[0015] In addition, the first anodic oxide film is composed solely of a barrier layer in which no pores are formed internally.

[0016] An inductor using a multilayer ceramic dielectric for an inductor according to another feature of the present invention comprises a coil portion and a multilayer ceramic dielectric for an inductor, wherein the coil portion comprises a plurality of vertical connection portions penetrating the multilayer ceramic dielectric for an inductor; an upper connection portion connecting the vertical connection portions at the upper portion of the multilayer ceramic dielectric for an inductor; and a lower connection portion connecting the vertical connection portions at the lower portion of the multilayer ceramic dielectric for an inductor, wherein the multilayer ceramic dielectric for an inductor comprises a surface layer composed of a first anodic oxide film having a relatively small porosity; and an inner layer provided at the lower portion of the surface layer and composed of a second anodic oxide film having a relatively large porosity.

[0017] Additionally, the surface layer comprises: an upper surface layer constituting the upper surface of the multilayer ceramic dielectric for the inductor; and a lower surface layer constituting the lower surface of the multilayer ceramic dielectric for the inductor.

[0018] The present invention comprises a first anodic oxide film having a low porosity by forming a relatively small diameter of pores or a relatively small number of pores on the upper and lower surface layers, and a second anodic oxide film having a high porosity by forming a relatively large diameter of pores or a relatively large number of pores on the inner layer located between the upper and lower surface layers, thereby forming a high dielectric constant on the upper and lower surfaces and a low dielectric constant in the inner region. Through this, the present invention provides a multilayer ceramic dielectric for an inductor and an inductor utilizing the same, wherein the current path operates efficiently on the surface side and the efficiency of magnetic field passage in the interior is increased to improve high-frequency characteristics.

[0019] FIG. 1 is a plan view of an inductor using a multilayer ceramic dielectric for an inductor according to a preferred first embodiment of the present invention.

[0020] FIG. 2 is a cross-sectional view taken along A-A' of FIG. 1.

[0021] FIG. 3 is a schematic diagram showing a multilayer ceramic dielectric for an inductor according to a preferred first embodiment of the present invention, viewed from the direction of cutting along A-A' of FIG. 1.

[0022] FIG. 4 is a schematic diagram showing a multilayer ceramic dielectric for an inductor according to a preferred second embodiment of the present invention, viewed from the direction of cutting along A-A' of FIG. 1.

[0023] FIG. 5 is a schematic diagram showing a multilayer ceramic dielectric for an inductor according to a preferred third embodiment of the present invention, viewed from the direction of cutting along A-A' of FIG. 1.

[0024] The following merely exemplifies the principles of the invention. Therefore, those skilled in the art may invent various devices that embody the principles of the invention and fall within the concept and scope of the invention, even if they are not explicitly described or illustrated in this specification. Furthermore, all conditional terms and embodiments listed in this specification are, in principle, explicitly intended only for the purpose of enabling an understanding of the concept of the invention and should be understood as not being limited to the embodiments and conditions specifically listed as such.

[0025] The aforementioned objectives, features, and advantages will become clearer through the following detailed description in conjunction with the attached drawings, and accordingly, a person skilled in the art to which the invention pertains will be able to easily implement the technical concept of the invention.

[0026] The embodiments described herein will be explained with reference to cross-sectional and / or perspective views, which are exemplary illustrations of the present invention. The thicknesses, etc., of films and regions depicted in these drawings are exaggerated for the effective explanation of the technical content. The shapes of the exemplary drawings may be modified by manufacturing techniques and / or tolerances, etc. Accordingly, the embodiments of the present invention are not limited to the specific shapes depicted but include variations in shape produced according to the manufacturing process. Technical terms used herein are used merely to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "comprising" are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described herein, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0027] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In describing various embodiments below, for convenience, the same name and reference number will be assigned to components performing the same function, even if the embodiments differ. Additionally, configurations and operations already described in other embodiments will be omitted for convenience.

[0028] FIG. 1 is a plan view of an inductor (100) using a multilayer ceramic dielectric (41) for an inductor according to a preferred first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along A-A' of FIG. 1, and FIG. 3 is a schematic view taken from the direction taken along A-A' of FIG. 1 of a multilayer ceramic dielectric (41) for an inductor according to a preferred first embodiment of the present invention.

[0029] Referring to FIGS. 1 to 3, an inductor (100) using a multilayer ceramic dielectric (41) for an inductor according to the first embodiment is configured to include a coil portion (10) and a multilayer ceramic dielectric (41) for an inductor according to the first embodiment.

[0030] The coil portion (10) is composed of an electrically conductive material and, preferably, can be formed by including a metal with high electrical conductivity. For example, the material constituting the coil portion (10) includes silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), copper (Cu), platinum (Pt), or an alloy thereof.

[0031] The coil portion (10) includes a winding portion (20) and a pad portion (30). The pad portion (30) includes a first pad portion (31) connected to one end of the winding portion (20) and a second pad portion (32) connected to the other end of the winding portion (20). The winding portion (20) is formed between the first and second pad portions (31, 32). The first pad portion (31) is connected to a first external electrode (not shown), and the second pad portion (32) is connected to a second external electrode (not shown). The first and second external electrodes are formed from copper (Cu), nickel (Ni), tin (Sn), or an alloy thereof. The first and second pad portions (31, 32) may both be provided on the same surface, for example, the upper surface, of the multilayer ceramic dielectric (41) for the inductor of the first embodiment. However, they are not limited thereto.

[0032] The winding section (20) includes a plurality of vertical connecting sections (21) that penetrate the multilayer ceramic dielectric (41) for the inductor of the first embodiment and a horizontal connecting section (25) that connects the vertical connecting sections (21). The winding section (20) is formed such that the horizontal connecting section (25) is provided on the outside of the multilayer ceramic dielectric (41) for the inductor of the first embodiment, and the vertical connecting section (21) is provided on the inside of the multilayer ceramic dielectric (41) for the inductor of the first embodiment, and is wound to wrap around a portion of the multilayer ceramic dielectric (41) for the inductor of the first embodiment.

[0033] The vertical connection portion (21) is formed by filling an electrically conductive material into a vertical penetration portion (24) that penetrates the multilayer ceramic dielectric (41) for the inductor of the first embodiment from top to bottom. The vertical connection portion (21) includes a first row of vertical connection portions (22) located on one side of the multilayer ceramic dielectric (41) for the inductor of the first embodiment and a first row of vertical connection portions (23) located on the other side of the multilayer ceramic dielectric (41) for the inductor of the first embodiment. The vertical connection portions (21) arranged in a row direction are spaced apart from each other by a certain distance.

[0034] The horizontal connection portion (25) is provided on the surface side of the multilayer ceramic dielectric (41) for the inductor of the first embodiment and is composed of an electrically conductive material. The horizontal connection portion (25) may be the same material as the vertical connection portion (21). The horizontal connection portion (25) includes an upper connection portion (26) that connects the vertical connection portions (21) at the upper end of the multilayer ceramic dielectric (41) for the inductor of the first embodiment, and a lower connection portion (27) that connects the vertical connection portions (21) at the lower end of the multilayer ceramic dielectric (41) for the inductor of the first embodiment.

[0035] The upper connecting part (26) is configured to connect the vertical connecting part (21) of any one of the vertical connecting parts (22) of the first row and the vertical connecting part (21) of the first row that is at the shortest distance from the vertical connecting part (23) of the first row. The upper connecting part (26) may be provided as a diagonal line having an upward inclination to the right based on the drawing of FIG. 1. The vertical connecting parts (21) arranged in the row direction are spaced apart from each other by a certain distance. Accordingly, the upper connecting parts (26) have an inclination of the same angle.

[0036] The lower connecting part (27) is configured to connect the vertical connecting part (21) that is at the shortest distance among any one of the vertical connecting parts (23) of the first row and the vertical connecting part (21) of the first row (22). The lower connecting part (27) may be provided as a diagonal line having an upward-left slope based on the drawing of FIG. 1. The vertical connecting parts (21) arranged in the row direction are spaced apart from each other by a certain distance. Accordingly, the lower connecting parts (27) have the same angle of inclination.

[0037] The upper connecting part (26) and the lower connecting part (27) are connected through the vertical connecting part (21), and the coil is wound in a shape that penetrates the multilayer ceramic dielectric (41) for the inductor of the first embodiment through the vertical connecting part (21). The internal region of the coil part (10) formed by the first and second rows of vertical connecting parts (21) and the upper and lower connecting parts (27) has a square cross-sectional shape.

[0038] When the first column of vertical connecting parts (22) is projected toward the first column of vertical connecting parts (23), the first column of vertical connecting parts (22) is located at a distance between the first column of vertical connecting parts (23). If a virtual line is drawn connecting the two adjacent vertical connecting parts (22) in the first column of vertical connecting parts (22) and the vertical connecting part (23) located between them when projected onto the first column of vertical connecting parts (23), the virtual line becomes the hypotenuse of an isosceles triangle. In other words, if a virtual line is drawn connecting the center point of each of the two adjacent vertical connecting parts (22) in the first column of vertical connecting parts (22) and the center point of the vertical connecting part (23) located between them when projected onto the first column of vertical connecting parts (23), the virtual line becomes the hypotenuse of an isosceles triangle. Through this, the difference between the direction of the magnetic flux generated by the lower connection part (27) and the direction of the magnetic flux generated by the upper connection part (26) is minimized, thereby enabling a more stable inductance. Additionally, by making the lengths of the upper connection part (26) and the lower connection part (27) equal, the time the current flows through the upper connection part (26) and the time it flows through the lower connection part (27) are equal, thereby enabling a stable inductance.

[0039] The multilayer ceramic dielectric (41) for an inductor of the first embodiment is composed of an anodic oxide film material and has a structure that joins a plurality of stacked anodic oxide films (80) through a bonding layer (400). The bonding layer (400) is located between each of the anodic oxide films (80).

[0040] The bonding layer (400) can be provided by a photoresist process. The bonding layer (400) can be composed of a photosensitive material having photosensitive properties. As an example, the bonding layer (400) may be a Dry Film Photoresist (DFR). Additionally, since the bonding layer (400) performs the function of bonding the surface layer (including the upper and lower surface layers (61, 62)) and the inner layer (70), it can be configured to have bonding properties. Therefore, the bonding layer (400) can be provided to have a configuration that simultaneously possesses photosensitive properties and bonding properties. When using a bonding layer (400) of such a material, in addition to the bonding function, it can also perform a mask function that can be used to form a vertical penetration (24) in the anodic oxide film material by utilizing the opening area of ​​the bonding layer (400).

[0041] Meanwhile, the bonding layer (400) may be a thermosetting resin. As a thermosetting resin material, it may be a polyimide resin, a polyquinoline resin, a polyamideimide resin, an epoxy resin, a polyphenylene ether resin, and a fluoropolymer resin.

[0042] Additionally, the bonding layer (400) may be provided as a ceramic bonding layer. The ceramic bonding layer has the advantage of allowing the inductor to be used even in a high-temperature environment.

[0043] Additionally, the bonding layer (400) may be provided with solder.

[0044] The bonding layer (400) bonds the surface layer (60) and the inner layer (70). As a result, the vertical penetration portion (24) is formed to penetrate the surface layer (60) and the inner layer (70) vertically and completely.

[0045] The anodic oxide film (80) refers to a film formed by anodic oxidation of a base metal. A pore refers to a hole formed during the process of anodic oxidation of a base metal to form the anodic oxide film. For example, if the base metal is aluminum (Al) or an aluminum alloy, an anodic oxide film (80) made of aluminum oxide (Al2O3) is formed on the surface of the base metal when the base metal is anodic. The anodic oxide film (80) formed as described above is vertically divided into a barrier layer (300) in which no pores (201) are formed inside, and a porous layer (200) in which pores (201) are formed inside. When the base metal having the anodic oxide film (80) having the barrier layer (300) and the porous layer (200) formed on its surface is removed, only the anodic oxide film (80) made of aluminum oxide (Al2O3) remains.

[0046] The anodic oxide film (80) may be formed such that the barrier layer (300) formed during anodic oxidation is removed, allowing only the pores (201) to penetrate from top to bottom, or such that the barrier layer (300) formed during anodic oxidation remains intact, sealing one end of the upper or lower portion of the pores (201). Additionally, the anodic oxide film (80) may be formed such that the barrier layer (300) is formed without the pores (201), thereby providing only the barrier layer (300).

[0047] The anodic oxide film (80) has a coefficient of thermal expansion of 2 to 3 ppm / ℃. As a result, when exposed to a high-temperature environment, there is less thermal deformation due to temperature. The inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment includes a coil portion (10). The inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment must not deform by reacting sensitively to the temperature of the surrounding environment.

[0048] The inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can minimize its own thermal deformation by configuring the multilayer ceramic dielectric (41) for the inductor of the first embodiment with an anodic oxide film material. As a result, it is possible to prevent the coil of the coil portion (10) from breaking or the inductance from changing.

[0049] In the method for manufacturing an inductor (100) using a multilayer ceramic dielectric (41) for an inductor according to the first embodiment, a vertical penetration portion (24) is provided in the multilayer ceramic dielectric (41) for an inductor according to the first embodiment through a process of wet etching the anodic oxide film (80) using a patterned photoresist. Accordingly, the vertical penetration portion (24) has an inner wall with a vertical shape. In other words, it is possible to have the same cross-sectional area of ​​the inner wall of the vertical penetration portion (24) from the bottom to the top of the vertical penetration portion (24). Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for an inductor according to the first embodiment can stably form the current flow of the coil portion (10).

[0050] One method to improve the inductance of an inductor is to increase the area of ​​the body around which the coil is wound. To this end, the inductor (100) using the multilayer ceramic dielectric (41) for an inductor of the first embodiment applies the multilayer ceramic dielectric (41) for an inductor of the first embodiment having a structure in which a plurality of anodic oxide films (80) are stacked.

[0051] The multilayer ceramic dielectric (41) for an inductor of the first embodiment is provided with a plurality of anodic oxide films (80), and is configured by stacking anodic oxide films (80) having different porosities. In the multilayer ceramic dielectric (41) for an inductor of the first embodiment, an anodic oxide film (80) with a relatively small porosity is placed on the surface (upper and lower surfaces), and an anodic oxide film (80) with a relatively large porosity is placed inside.

[0052] Referring to FIGS. 2 and 3, the multilayer ceramic dielectric (41) for an inductor of the first embodiment comprises a surface layer (60) composed of a first anodic oxide film (81) having a relatively small porosity and an inner layer (70) provided below the surface layer (60) and composed of a second anodic oxide film (90) having a relatively large porosity. That is, the porosity of the first anodic oxide film (81) is relatively smaller than the porosity of the second anodic oxide film (90).

[0053] In the present invention, porosity refers to the volume occupied by empty space per unit volume. Accordingly, the first anodic oxide film (81) of the surface layer (60) is composed of an anodic oxide film (80) with low porosity, where the volume occupied by the pores (201) is relatively small, and the second anodic oxide film (90) of the inner layer (70) is composed of an anodic oxide film (80) with high porosity, where the volume occupied by the pores (201) is relatively large.

[0054] The size of the porosity of the anodic oxide film (80) can be controlled by forming a small diameter of the pores (201) or forming a low density of the pores (201) (number of pores (201) per unit volume) during the process of manufacturing the anodic oxide film (80). Alternatively, the size of the porosity of the anodic oxide film (80) can be controlled by forming through holes penetrating the anodic oxide film (80) through a separate etching process.

[0055] The multilayer ceramic dielectric (41) for an inductor of the first embodiment preferably has a structure in which at least three or more anodic oxide films (80) are stacked. Accordingly, the multilayer ceramic dielectric (41) for an inductor of the first embodiment may be composed of a surface layer (60) consisting of anodic oxide films (80) located on the upper and lower surface sides, and an inner layer (70) provided on the lower side of the surface layer (60).

[0056] Specifically, the surface layer (60) is configured to include an upper surface layer (61) constituting the upper surface of the multilayer ceramic dielectric (41) for the inductor of the first embodiment and a lower surface layer (62) constituting the lower surface of the multilayer ceramic dielectric (41) for the inductor of the first embodiment.

[0057] The upper surface layer (61) is provided on the upper part of the inner layer (70).

[0058] The upper surface layer (61) is composed of a first anodic oxide film (81) with a relatively small porosity. The first anodic oxide film (81) may be composed of a porous layer (200) having pores (201) formed inside.

[0059] The first anodic oxide film (81) can have a smaller porosity than the second anodic oxide film (90) constituting the inner layer (70) by forming the diameter of the pores (201) smaller.

[0060] In contrast, the first anodic oxide film (81) may have a number of pores (201) per unit volume that is smaller than the number of pores (201) per unit volume of the second anodic oxide film (90). Through this, the first anodic oxide film (81) may have a lower density of pores (201) than the second anodic oxide film (90) and thus may have a small porosity.

[0061] The lower surface layer (62) is provided at the bottom of the inner layer (70).

[0062] The lower surface layer (62) is composed of a first anodic oxide film (81) having a relatively small porosity, similar to the upper surface layer (61). The first anodic oxide film (81) may be composed of a porous layer (200) having pores (201) formed inside. The first anodic oxide film (81) may have a small porosity by having a low density of pores (201) by forming the diameter of the pores (201) of the first anodic oxide film (81) smaller than the diameter of the pores (201) of the second anodic oxide film (90), or by having the number of pores (201) per unit volume of the first anodic oxide film (81) smaller than the number of pores (201) per unit volume of the second anodic oxide film (90).

[0063] The multilayer ceramic dielectric (41) for an inductor of the first embodiment is composed of upper and lower surface layers (61, 62) with a first anodic oxide film (81) having a small porosity. Through this, the multilayer ceramic dielectric (41) for an inductor of the first embodiment can form a surface (including upper and lower surfaces) with a small porosity.

[0064] Since a strong magnetic field is generated near the coil of an inductor, it is required to form a high dielectric constant on the surface side of the body where the coil is wound.

[0065] Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment has a small porosity of the anodic oxide film (80) located on the upper and lower surface layers (61, 62) near the coil portion (10). As a result, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can form a high dielectric constant of the upper and lower surface layers (61, 62) near the coil portion (10).

[0066] Specifically, the upper and lower surface layers (61, 62) of the multilayer ceramic dielectric (41) for an inductor of the first embodiment, on which the coil portion (10) is wound, are composed of a first anodic oxide film (81) with a small porosity. As a result, the porosity of the upper and lower surfaces is small. Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for an inductor of the first embodiment can form a high dielectric constant on the upper and lower surfaces near the coil portion (10).

[0067] More specifically, the multilayer ceramic dielectric (41) for an inductor of the first embodiment has a small porosity on the upper surface through an upper surface layer (61) composed of a first anodic oxide film (81) with small porosity. As a result, the multilayer ceramic dielectric (41) for an inductor of the first embodiment can form a strong electric field by forming a high dielectric constant near the upper connection part (26).

[0068] In addition, the multilayer ceramic dielectric (41) for an inductor of the first embodiment has a low porosity on its lower surface through a lower surface layer (62) composed of a first anodic oxide film (81) with low porosity. As a result, the multilayer ceramic dielectric (41) for an inductor of the first embodiment can form a strong electric field by forming a high dielectric constant near the lower connection part (27).

[0069] Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can efficiently operate the current path of the horizontal connection part (25).

[0070] The inner layer (70) is provided below the surface layer (specifically, the upper surface layer (61)) and is located between the upper and lower surface layers (61, 62).

[0071] The inner layer (70) is composed of a second anodic oxide film (90) with a relatively large porosity. The second anodic oxide film (90) may be composed only of a porous layer (200) in which pores (201) are formed inside.

[0072] The second anodic oxide film (90) can have a larger porosity than the first anodic oxide film (81) constituting the inner layer (70) by forming a larger diameter of the pores (201).

[0073] In contrast, the second anodic oxide film (90) may have a greater number of pores (201) per unit volume than the number of pores (201) per unit volume of the first anodic oxide film (81). Through this, the second anodic oxide film (90) may have a higher density of pores (201) than the first anodic oxide film (81) and thus may have a large porosity. Alternatively, the second anodic oxide film (90) may have a large porosity by etching and removing at least a portion of the second anodic oxide film (90) separately from the pores (201).

[0074] The inner layer (70) is a region through which a magnetic field passes, and is a region that must have a low dielectric constant. The inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can have a low dielectric constant by configuring the inner layer (70) with a second anodic oxide film (90) with a large porosity. Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can operate efficiently at high frequencies.

[0075] In the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment, a first anodic oxide film (81) having a low porosity is positioned on the upper and lower surface layers (61, 62) by forming the diameter of the pores (201) relatively small or having a relatively small number of pores (201). On the inner layer (70) located between the upper and lower surface layers (61, 62), a second anodic oxide film (90) having a high porosity is positioned by forming the diameter of the pores (201) relatively large or having a relatively large number of pores (201).

[0076] Accordingly, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment has a structure in which a first anodic oxide film (81) with low porosity, a second anodic oxide film (90) with high porosity, and a first anodic oxide film (81) with low porosity are arranged in a vertical direction from top to bottom.

[0077] Through this, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment can form a high dielectric constant on the upper and lower surfaces of the multilayer ceramic dielectric (41) for the inductor of the first embodiment located near the coil portion (10).

[0078] Meanwhile, in the inner layer (70) located between the upper and lower surface layers (61, 62) and not exposed to the surface, the dielectric constant is formed low through the second anodic oxide film (90) with a large porosity. Accordingly, the inductor (100) of the multilayer ceramic dielectric (41) for the inductor of the first embodiment can have a low dielectric constant in the inner region through which the magnetic field passes.

[0079] As a result, the inductor (100) using the multilayer ceramic dielectric (41) for the inductor of the first embodiment has a high dielectric constant formed on the surface side so that the current path operates efficiently, and has a low dielectric constant formed internally so that the efficiency of magnetic field passage is increased and high-frequency characteristics can be improved.

[0080] FIG. 4 is a schematic diagram showing a multilayer ceramic dielectric (42) for an inductor according to a preferred second embodiment of the present invention, viewed from the direction of cutting along A-A' of FIG. 1.

[0081] The second embodiment described below will be explained focusing on characteristic components compared to the first embodiment, and components identical or similar to those of the first embodiment are utilized in the composition of the second embodiment, with descriptions thereof omitted as much as possible.

[0082] The multilayer ceramic dielectric (42) for an inductor of the second embodiment can function as a body on which a coil portion (10) is wound, as an example, by being applied to an inductor. The inductor to which the multilayer ceramic dielectric (42) for an inductor of the second embodiment is applied can have the same structure as the inductor (100) using the multilayer ceramic dielectric (41) for an inductor of the first embodiment.

[0083] The multilayer ceramic dielectric (42) for an inductor of the second embodiment can form a vertical penetration portion (24) when applied to an inductor and can provide a vertical connection portion (21).

[0084] The multilayer ceramic dielectric (42) for an inductor of the second embodiment has a structure in which three anodic oxide films (80) are stacked and bonded through a bonding layer (400).

[0085] The multilayer ceramic dielectric (42) for an inductor of the second embodiment has a first anodic oxide film (82) having a small porosity placed on the upper and lower surface layers (61, 62), and a second anodic oxide film (90) having a large porosity placed on the inner layer (70).

[0086] The first anodic oxide film (82) of the upper and lower surface layers (61, 62) is configured to include a barrier layer (300) in which no pores (201) are formed inside, and a porous layer (200) provided on one side of the barrier layer (300) in which pores (201) are formed inside.

[0087] The multilayer ceramic dielectric (42) for an inductor of the second embodiment is provided with a first anodic oxide film (82) on the upper and lower surface layers (61, 62), and arranged so that the barrier layer (300) is located on the surface side.

[0088] The multilayer ceramic dielectric (42) for an inductor of the second embodiment has an upper surface that is closed by a barrier layer (300). Specifically, the first anodic oxide film (82) disposed on the upper surface layer (61) is provided in a structure in which the barrier layer (300) is located on the upper surface of the porous layer (200), so that the barrier layer (300) of the first anodic oxide film (82) forms the upper surface of the multilayer ceramic dielectric (42) for an inductor of the second embodiment. Accordingly, there are no pores (201) on the upper surface of the upper surface layer (61) of the multilayer ceramic dielectric (42) for an inductor of the second embodiment, and a porous layer (200) having a small porosity exists on the lower surface.

[0089] The multilayer ceramic dielectric (42) for an inductor of the second embodiment has a lower surface that is closed by a barrier layer (300). The first anodic oxide film (82) disposed on the lower surface layer (62) is provided in a structure in which the barrier layer (300) is located below the porous layer (200), so that the barrier layer (300) of the first anodic oxide film (82) forms the lower surface of the multilayer ceramic dielectric (42) for an inductor of the second embodiment. Accordingly, there are no pores (201) on the lower surface of the lower surface layer (62) of the multilayer ceramic dielectric (42) for an inductor of the second embodiment, and a porous layer (200) having a small porosity exists below it.

[0090] The multilayer ceramic dielectric (42) for an inductor of the second embodiment is provided with a first anodic oxide film (82) having a structure having a barrier layer (300) and a porous layer (200) on each of the upper surface layer (61) and the lower surface layer (62), and arranged so that the barrier layer (300) is located on the surface side of each layer.

[0091] In this way, the multilayer ceramic dielectric (42) for an inductor of the second embodiment has a barrier layer (300) located on the upper and lower surface sides by placing a first anodic oxide film (82) on the upper and lower surface layers (61, 62). Accordingly, when the multilayer ceramic dielectric (42) for an inductor of the second embodiment is applied to an inductor, it can form a high dielectric constant near the coil portion (10).

[0092] Meanwhile, the inner layer (70) is composed of a second anodic oxide film (90) having a greater porosity than the first anodic oxide film (82).

[0093] At this time, the second anodic oxide film (90) is composed only of a porous layer (200) in which pores (201) are formed.

[0094] The inner layer (70) is a region through which a magnetic field passes. In the second embodiment, the multilayer ceramic dielectric (42) for an inductor is composed of the second anodic oxide film (90) of the inner layer (70) as a porous layer (200) in which pores (201) are formed, and the porosity is greater than that of the porous layer (200) of the first anodic oxide film (82). Accordingly, the inner layer (70) can form a low dielectric constant between the upper and lower surface layers (61, 62). Therefore, the multilayer ceramic dielectric (42) for an inductor in the second embodiment can enable the inductor to operate efficiently at high frequencies.

[0095] The multilayer ceramic dielectric (42) for an inductor of the second embodiment has different porosity for the first anodic oxide film (82) provided on the upper and lower surface layers (61, 62) and the second anodic oxide film (90) provided on the inner layer (70), and has different structure for the first anodic oxide film (82) and the second anodic oxide film (90).

[0096] Specifically, the first anodic oxide film (82) is provided with a structure of a barrier layer (300) in which pores (201) are not formed and a porous layer (200) in which pores are formed, wherein the barrier layer (300) is positioned on the surface side.

[0097] In contrast, the second anodic oxide film (90) is provided with a structure having only a porous layer (200) in which pores (201) are formed, and is placed between the upper and lower surface layers (61, 62).

[0098] Accordingly, when the multilayer ceramic dielectric (42) for the inductor of the second embodiment is applied to the inductor, it forms a high dielectric constant near the coil portion (10), thereby enabling the current path to operate efficiently. In addition, it forms a low dielectric constant internally to increase the efficiency of magnetic field passage, thus improving the high-frequency characteristics of the inductor.

[0099] FIG. 5 is a schematic diagram showing a multilayer ceramic dielectric (43) for an inductor according to a preferred third embodiment of the present invention, viewed from the direction of cutting along A-A' of FIG. 1.

[0100] The third embodiment described below will focus on characteristic components compared to the first embodiment, and components identical or similar to those of the first embodiment will be utilized in the composition of the third embodiment, with descriptions thereof omitted as much as possible.

[0101] The multilayer ceramic dielectric (43) for an inductor of the third embodiment can function as a body on which a coil portion (10) is wound, as an example, by being applied to an inductor. The inductor to which the multilayer ceramic dielectric (43) for an inductor of the third embodiment is applied can have the same structure as the inductor (100) using the multilayer ceramic dielectric (41) for an inductor of the first embodiment.

[0102] The first anodic oxide film (83) of the upper and lower surface layers (61, 62) is composed only of a barrier layer (300) in which no pores (201) are formed inside. Accordingly, the upper and lower surfaces of the multilayer ceramic dielectric (43) for an inductor of the third embodiment are composed of a barrier layer (300).

[0103] The multilayer ceramic dielectric (43) for an inductor of the third embodiment has a structure in which pores (201) are not provided on the upper and lower surfaces by providing a first anodic oxide film (83) composed only of a barrier layer (300) on the upper and lower surface layers (61, 62).

[0104] Accordingly, the multilayer ceramic dielectric (43) for the inductor of the third embodiment can have a higher dielectric constant on the upper and lower surfaces.

[0105] The inner layer (70) is composed of a second anodic oxide film (90) having a porosity. The second anodic oxide film (90) is composed only of a porous layer (200) in which pores (201) are formed.

[0106] The multilayer ceramic dielectric (43) for an inductor of the third embodiment forms upper and lower surfaces through a barrier layer (300) in which pores (201) do not exist, and forms an internal region through a second anodic oxide film (90) composed only of a porous layer (200) with a high porosity.

[0107] Accordingly, the multilayer ceramic dielectric (43) for the inductor of the third embodiment can form a high dielectric constant near the coil portion (10) to efficiently operate the current path. In addition, by forming a low dielectric constant internally to increase the magnetic field passage efficiency, the high-frequency characteristics of the inductor can be improved.

[0108] As described above, although the present invention has been explained with reference to preferred embodiments, a person skilled in the art may implement the present invention with various modifications or variations without departing from the spirit and scope of the invention as described in the following claims.

[0109] [Explanation of the symbol]

[0110] Main symbols of the drawing

[0111] 100: Inductor using multilayer ceramic dielectric for inductors

[0112] 10: Coil part

[0113] 20: Gwonseonbu

[0114] 30: Pad section

[0115] 41, 42, 43: Multilayer ceramic dielectric for inductors

[0116] 80: Anodic oxide film

[0117] 81, 82, 83: First anodic oxide film

[0118] 90: Second anodic oxide film

[0119] 200: Porous layer

[0120] 300: Barrier layer

Claims

1. A surface layer composed of a first anodic oxide film having a relatively small porosity; and A multilayer ceramic dielectric for an inductor comprising: an inner layer provided below the surface layer and composed of a second anodic oxide film having a relatively large porosity.

2. In Paragraph 1, The above surface layer is, An upper surface layer constituting the upper surface of the multilayer ceramic dielectric for the above inductor; and A multilayer ceramic dielectric for an inductor comprising: a lower surface layer constituting the lower surface of the multilayer ceramic dielectric for an inductor.

3. In Paragraph 1, The first anodic oxide film and the second anodic oxide film are composed of a porous layer having pores formed therein, and A multilayer ceramic dielectric for an inductor, wherein the diameter of the pores in the porous layer of the first anodic oxide film is smaller than the diameter of the pores in the porous layer of the second anodic oxide film.

4. In Paragraph 1, The first anodic oxide film and the second anodic oxide film are composed of a porous layer having pores formed inside, and A multilayer ceramic dielectric for an inductor, wherein the pore density of the porous layer of the first anodic oxide film is lower than the pore density of the porous layer of the second anodic oxide film.

5. In Paragraph 1, The above first anodic oxide film is composed of a barrier layer having no pores formed therein and a porous layer having pores formed therein, provided on one side of the barrier layer. A multilayer ceramic dielectric for an inductor, wherein the above barrier layer is located on the surface side.

6. In Paragraph 1, The above-mentioned first anodic oxide film is a multilayer ceramic dielectric for an inductor, composed only of a barrier layer in which no pores are formed internally.

7. In an inductor using a coil portion and a multilayer ceramic dielectric for the inductor, The above coil part is, A plurality of vertical connection portions penetrating the multilayer ceramic dielectric for the inductor; An upper connecting portion connecting the vertical connecting portions at the top of the multilayer ceramic dielectric for the inductor; and It includes a lower connection portion connecting the vertical connection portions at the bottom of the multilayer ceramic dielectric for the inductor, and The above-mentioned multilayer ceramic dielectric for the inductor is, A surface layer composed of a first anodic oxide film with a relatively small porosity; and An inductor using a multilayer ceramic dielectric for an inductor, comprising: an inner layer provided below the surface layer and composed of a second anodic oxide film having a relatively large porosity.

8. In Paragraph 7, The above surface layer is, An upper surface layer constituting the upper surface of the multilayer ceramic dielectric for the above inductor; and An inductor using a multilayer ceramic dielectric for an inductor, comprising: a lower surface layer constituting the lower surface of the multilayer ceramic dielectric for an inductor.

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